Pneumatic displacement pump



INVENTOR 5 Sheets-Sheet 1 Aug. 26, 1958 Filed June '7. 1957 50)/5 M/V/LE/P,

BY @MLM ATTORNEY 5 Sheets-Sheet 2 D. H. MILLER PNEUMATIC DISPLACEMENT PUMP Aug. 26, 1958 Filed June 7, 1957 ATTORN D. H. MILLER PNEUMATIC DISPLACEMENT PUMP Aug. 26, 1958 Filed June 7; 1957 3 Sheets-Sheet 5 United States Patent O fc" PNEUMATIC DSPLACEMENT PUMP lDoyle H. Miller, Corpus Christi, Tex.

Application June '7, 1957, Serial No. 664,328

6 Claims. (Cl. 10S-240) The invention relates to pneumatic displacement pumps, for example, those used in automatic water systems.

A primary object of the invention is to provide a pneumatic displacement pump of highly simplified and rugged construction, and characterized particularly by a highly simplified compressed air inlet and exhaust valve arrangement.

A further important object of the invention is to provide a pump of the above-mentioned character which is entirely free of springs throughout its construction, as well as other parts subject to corrosion.

A further object is to provide a pneumatic displacement pump which is highly efficient and positive in operation, so as to be capable of providing a substantially continuous ilo-w of liquid at the desired point of delivery.

A further object is to provide a pump of the abovementioned character which is highly inexpensive to manufacture, compared to prior art pumps of the same general character.

An additional object of the invention is to provide a pneumatic displacement pump capable of a wide variety of uses such as elevating water from a well, holding the liquid 4level in a sump, providing a bilge pump for boats, supplying water for lawn sprinkler systems and other similar uses.

Other objects `and advantages of the invention will be apparent during the course of the following description.

In the accompanying drawings, forming a part of this application, and in which like numerals are employed to designate like parts throughout the same,

Figure l is a side elevation on a greatly reduced scale of a pneumatic displacement pump embodying the invention in place within a well.

Figure 2 is an enlarged central vertical longitudinal section through the pump mechanism with parts broken away.

Figure 3 is a horizontal transverse section taken on line 3-3 of Figure 2.

Figure 4 is a similar section taken on line 4-4 of Figure 2.

Figure 5 is a fragmentary vertical section taken on line 5-5 of Figure 3.

Figure 6 is a similar section taken on line 6 6 of Figure 3.

Figure 7 is an end elevation of a spool-like valve body 1 removed.

Figure 8 is a fragmentary side elevation on a reduced scale of a oat and associated elements.

In the drawings, wherein for the purpose of illustration is shown a preferred embodiment of the invention, attention is directed first to Figure 1, wherein the numeral 10 designates a well or cistern containing a body 11 of liquid to be elevated under pressure by the pump of the present invention and discharged into a suitable delivery system which may include the pipe 12.

With reference to the other figures, the pump proper comprises a barrel or cylinder 13 having its opposite grooves 40 and 41, the former groove being in direct Patented Aug. 26, 1958 ends closed by upper and lower pump heads 14 and-15, rigidly secured thereto and forming uid tight joints therewith through the medium of suitable seals 16 and 17. The barrel 13 and heads 14 and 15 together define a liquid receiving chamber 18 into which the liquid flows under hydrostatic pressure, and from which the liquid is automatically pumped, as will be fully apparent.

The lower head 15 is provided in its periphery with an annular groove 19, preferably covered by `a screen or strainer 20 secured at 21 to the head 15. The annular groove 19 communicates directly with a plurality of radial ports 22 formed in the lower pump head, and in turn communicating at their inner ends with a corresponding number of axial ports Z3, the latter opening through the top of the head 15.

A central axial uid discharge pipe 24 extends between the heads 14 and 15 and has screw-threaded end portions secured in screw-threaded engagement within screwthreaded openings 25 and 26 of the heads 14 and 15 respectively. As shown in Figure 2, just above the lower head 15, the discharge pipe 24 is provided in its side wall with a large inlet opening 27, to admit liquid from the chamber 18 into the discharge pipe 24. The usual foot valve ring 28 surrounds the pipe 24 and is movable axially thereof and this foot valve ring is adapted to cover an-d close the tops of the ports 23, when in the lowered position and resting upon the top face of the lower head 15.

A suitable i'loat 29 also surrounds the pipe 24 within the chamber 1S and is freely movable longitudinally of the pipe 24. An annular bumper washer 3d of resilient material is carried by the top of the float 2.9 to protect the float, as shown.

The upper end of the pipe 24 communicates directly with a central axial passage or opening 31, formed through the upper head 14, and the head 14 is further provided at the top of the passage 31 with a screwthreaded opening 32, for receiving the lower screwthreaded end 33 of a long vertical pump discharge pipe 34. The pipe 34 leads to and is connected with the pipe 12, as shown in Figure l.

Connected in the pump discharge pipe 34, just above the upper head 14, is a ball check valve 35 to prevent liquid in the pump discharge pipe 34 from flowing back into the pump chamber 18, The ball check valve 35 opens automatically to permit the free flow of liquid upwardly within the discharge pipe 34.

The upper pump head 14 carries and houses the air inlet and exhaust valve means of the pump, as will now become apparent.

With particular reference to Figures 3 and 5, the pump head 14 is provided with a first transverse cylindrical bore 36 to receive and house the automatic air inlet valve means presently to be described. As shown in Figure 3, the bore 36 is offset with respect to the central longitudinal axis of the head 14 and pump barrel 13. The pump head 14 is further provided at the transverse center of the bore 36 and near the longitudinal center thereof with a relatively large port 37 in direct communication with the bore 36 and opening through the bottom of the head 14, so as to communicate directly with the chamber lil.

The bore 36 is formed to provide therein an annular shoulder 3S, arranged somewhat closer to one end of the bore 36 than to its opposite end, as shown. Removably mounted within the bore 36 upon one side of the shoulder 3S and engaging such shoulder is a spool-like valve body 39. This valve body 39 is provided in its periphery with axially spaced relatively large annular communication with the large port 37, Figure 5. The

valve body 39 is preferably provided upon opposite sides of the large groove 40 with suitable seals 41 and 42, forming fluid tight joints with `the cylindrical bore 36. The valve body 39 has an outer screw-threaded end portion 43, having screw-threaded engagement within a screwthreaded portion 44 of the bore 36, as indicated. The valve body 39 may also have a polygonal cap extension 45 formed integral therewith, and engageable by a wrench or the like for tightening the valve body into place within the bore 36.

As shown in Figures and 7, the valve body 39 is further provided with a relatively large central axial bore 46, opening through its end adjacent the shoulder 38. Surrounding the bore 46, in circumferentially spaced relation, are a plurality of relatively small axial ports 47, likewise opening through the adjacent end of the valve body 39, and communicating `directly with the large annular groove 40. A plurality of radial ports 48 extend from the closed end of the axial port 46 outwardly for direct communication with the annular groove 41, Figure 5.

A second removable inlet air valve body or portion 49 engages within the opposite end of the bore 36, upon the opposite side of the annular shoulder 38. The valve body 49 preferably has its inner end engaging a compressible seal 50 at the shoulder 38, as indicated. The valve body 49 is screw-threaded at 51 for engagement within a screw-threaded portion 52 of the bore 36. The valve body 49 may also be provided with a polygonal wrenchengaging head 53, as indicated.

lnwardly of its screw-threads 51, the valve body 49, is provided in its periphery with an annular groove 54, communicating with a relatively small radial port 55 within the valve body, in turn leading to and communieating with a central axial port S6, opening through the inner end of the valve body 49. The inner end of the valve body 49 may be centrally recessed at 57, as clearly shown in Figure 5, and the shoulder 38 serves to maintain the opposed ends of the valve bodies 39 and 49 spaced apart axially, for forming an internal cylindrical valve chamber S8 for an axially shiftable neoprene disc valve element S9.

With continue-d reference to Figure 5, the upper head 14 is provided near and below its top face and directlyl above the bore 36 with a small transverse air port 60,

having one end communicating at 61 with the annular "i groove 54. The other end of the air port 60 communicates with the bottom end of a compressed air inlet pipe 62, which pipe has screw-threaded engagement at 63 within a screw-threaded opening provided in the top of the head 14.

With reference to Figure l, the pipe 62 extends above the pump head 14, for connection above ground with an air compressor 63'.

Directly below the pipe 62, the pump head 14 may have an orifice plug 64, having an orice 65, allowing passage of most ot the compressed air from the pipe 62 into the groove 41, but diverting some air into the passage 60. The valve body 49 is provided as shown in Figure 5 with an L-shaped passage or port 66, communicating with the chamber 58 and leading to a vertical port 67 formed through the head 14, as indicated. An elbow 68 has screw-threaded engagement at 69 within a screw-threaded opening formed in the bottom of the head 14 adjacent to the port 67. The elbow 68 has an L-shaped passage 70, in direct communication with the port 67, but closed at its end remote from such port as shown at 71. A pilot valve sleeve 72 is mounted for rotation upon the horizontal portion of the elbow 68, Figure 5, and the sleeve 72 has a pair of diametrically opposed openings 73 formed therethrough, for registration with companion diametrically opposed openings 74 of the horizontal portion of the elbow 68. When the openings 73 and 74 are in complete registration, Figure 5, air under pressure from the port 67 may escape through the passage 70 of the elbow via the openings 74 and 73. The valve sleeve 4 72 has integrally secured to it a vertically swingable operating arm 75, which arm is arranged just below the bottom of the pump head 14 and spaced upon one side of the vertical pipe 24.

With reference to Figures 3 and 6, the pump head 14 is additionally provided with a second transverse cylindrical bore 76, parallel to and spaced from the bore 36 and arranged at the same elevation as the bore 36 within the head 14. As will become apparent, the bore 76 is adapted to house or contain the air exhaust valve means of the present pump. The bore 76 may conveniently be of the same diameter as the bore 36.

The bore 76 is formed to provide therein an annular shoulder 77, similar to the shoulder 38. Upon one side of this shoulder, and engaging the same, is a spool-like exhaust valve body 78, generally of cylindrical form, and provided in its periphery with a pair of axially spaced relatively large annular grooves 79 and 80, similar to the grooves 40 and 41. The valve body 78 is further provided with a central axial port 81 opening through the end of the valve body '78 which is adjacent the shoulder 77. Outwardly of the port 81, a plurality of relatively small axial ports 82, Figure 6, likewise open through the adjacent end of the valve `body 78 and also open into and communicate with the groove 79. A pair of seals 83 and 84 on opposite sides of the groove 79 form liquid tight joints between the valve body 78 and bore 76. Adjacent the opposite and closed end of the port 81, a plurality of relatively small radial ports 85 lead therefrom and open directly into the annular groove 80, The valve body 78 includes an outer screw-threaded portion 86, having screw-threaded engagement within a screwthreaded portion 87 of the bore 76. The valve body 78 may also have a polygonal cap or head 88 adapted to be engaged by a wrench or the like. Directly below the annular groove 80, the pump head 14 is further provided with a relatively large air exhaust port or passage 89, communicating directly with the pump chamber 18 and the groove 80. In like manner, directly above the annular groove 79, the lower screw-threaded end portion of an air exhaust pipe 90 has screw-threaded engagement at 91 within a screw-threaded opening formed through the top of the pump head 14, as shown. The exhaust pipe 90 is thus in direct communication with the annular passage 79, and as shown in Figure l, `the pipe 90 may extend above ground for exhausting the compressed air within the pump chamber 13 to the atmosphere.

Removably mounted within the other end of the cylindrical bore 76 is a second air exhaust valve body portion 92 having screw-threaded engagement at 93 within a screw-threaded opening or portion of the bore 76, the body portion 92 being likewise provided with a polygonal cap portion 94, as indicated. The inner end of the valve body portion 92 engages and compresses a suitable seal 95 at the shoulder 77. The valve body portion 92 is provided inwardly of its screw-threads 93 with an annular groove 96, forming an annular passage with the bore 76. A radial port 97 formed in the body portion 92 leads from the groove 96 to a central axial port 98 within the valve body portion 92, the axial port 98 opening through the inner end of the body portion 92. The inner end of the valve body portion 92 may be recessed as at 99, and the shoulder 77 serves to maintain the inner opposed ends of the valve bodies 78 and 92 spaced apart axially, for forming within the bore 76 ot the pump head 14 a cylindrical air exhaust chamber 100. Mounted within the chamber 108 for free axial movement is a neoprene exhaust disc valve element 101, which may be identical with the disc valve element 59.

Directly above the center of the bore 76, the head 14 of the pump is provided with a small vertical port 102 opening through the top of the pump head 14, and leading to a small horizontal port or passage 103, communieating at 164 with the annular groove 96 and radial port 97. The port 102 is connected by a tube 102 with the compressed air inlet pipe 62, just above the pump head 14, so that the ports 102, 103, etc. may receive air under pressurefrom the pipe 62. The valve body portion 92 is provided with a small L-shaped passage or port 105, registering and communicating with a vertical passage 106 within the pump head 14, opening through the bottom face of the latter.

An elbow 107 similar to the elbow 68 has screwthreaded engagement at S within a screw-threaded opening formed in the bottom of the pump head 14 adjacent the port 106. The elbow 107 has an L-shaped internal passage 109 in direct communication with the port 106 but closed at its end remote from this port, as showniat 110. The elbow .107 is provided in its horizontal portion with a pair of diametrically opposed ports or openings 111, adapted for registration with companion diametrically opposed ports 112 of an exhaust i sleeve pilot valve 113, which is mounted upon the hori- Zontal portion of the elbow 107 for rotation. The ports 112 are staggered or out of phase circumferentially with the ports 73, so that when the sleeve pilot valve 72 is opened, Figure 5, the sleeve pilot valve 113 will be closed, Figure 6. The sleeve pilot valve 113 is integrally connected with and operated by a vertically swingable arm 1141, similar to or identical with the arm 75.

As best shown in Figures 2 and 4, the vertically swingable arms 75 and 114 are arranged in spaced opposed relation beyond one side of the pipe 24. The arms are pivotally connected at 115 with short generally vertical links 116, in turn pivoted at their lower ends as indicated at 117 with a common connecting bracket or link 113. The bracket 118 has pivotally connected with it centrally thereof a long vertical connecting rod or link 119, which parallels the pipe 24 in spaced relation thereto. The connecting rod 119 extends downwardly from the bracket 118 and has its lower end pivotally secured at 120 with a swivel element or vertically swingable yoke 121. The yoke 121 extends beyond one side of the vertical pipe 24 for connection with the connecting rod 119, and the lower ends of the yoke 121 are pivotally secured at 122 with an annular washer 123, surrounding the pipe 241 and suitably fixed thereto. The washer 123 also serves as a stop to limit the upward movement of the foot valve ring 28.

The operation of the air displacement pump is as follows:

With the various parts arranged as shown in the drawings, and with the pilot valve operating arms 75 and 114 in their raised or uppermost positions, the openings 73 of the air inlet sleeve pilot valve 72 are in registration with the ports 74, whereas the openings 112 `of the exhaust sleeve pilot valve 113 are out of registration or closed with respect to the ports 111. Assume further that the pump barrel 13 and the upper pump head 14 are fully submerged within the body of water 11 within the well 10, Figure l, and the air compressor 63 is in operation to supply compressed air through the pipe 62 to the air inlet valve means of Figure 5.

The compressed air from the pipe 62 will pass simultaneously through the orifice 65 and into the groove 41 and also into the small port 60 of the head 14. Since the pilot valve openings 73 and 74 are in registration, the air under pressure from the port 60 may pass freely through the associated ports 55 and S6 and through the chamber 53 to the escape ports 66 and 67 which lead to the elbow 68. Consequently, no pressure will be built up within the chamber 58 behind the disc valve element 59, and the latter may readily shift to the left in Figure 5 or open under the intluence of the air pressure within the groove 41 and associated air passages. The compressed air from the groove 41 flows through the ports #t8 to the axial port 46 and from this port against the disc valve element 59 for shifting the same to the left or opening it in Figure 5. This uncovers the ports 47, and the compressed air enters these ports in the direction of the arrows, and Hows to the annular groove 40 and from this groove through the main compressed air inlet port 37 leading to the top of the pump chamber 1S.

While the above takes place, as previously suggested, the pilot valve ports 111 and 112 are closed or out of registration, and consequently the compressed air within the pump chamber 18 cannot be exhausted through the exhaust pipe and associated elements. This is true because the air pressure within the chamber and to the left o1 the disc valve element 101, Figure 6, will build up through tube 102 and increase for maintaining the disc valve 101 seated against the adjacent end of the valve body 73 in covering engagement with the ports S1 and S2. The air thus trapped within the chamber cannot escape through the ports 105 and 106 and through the elbow 107, since the ports 111 and 112 are not in registration. The compressed air within the pump chamber 18 may enter the passage 39 and groove 80, and may also ilow through the ports 85 to the axial port 81. However, such compressed air will not be able to unseat the exhaust disc valve element 101, since the exposed area of the same adjacent the chamber 100 is much greater than the exposed area at the axial port 81.

With this arrangement, the compressed air continually flowing into the pump chamber 1S from the passage 37 and trapped therein by means of the exhaust valve element 101, will exert a downward pressure upon the volume of water or other liquid within the chamber 18, and this pressure will also maintain the foot valve ring 28 seated upon the top of the lower pump head 15, in covering engagement with the several ports 23. Consequently, the water within the pump chamber 1S cannot escape through the ports 23, and the water must enter the relatively large opening 27 of the discharge pipe 24. This occurs, and the water within the chamber 18 is elevated through the -discharge pipe 24 and then through the pipe 34, which ultimately leads to the pipe 12 above ground. As stated previously, the one Way check valve 35 allows the uid or water to flow freely upwardly through the pipe 34, 'but prevents such fluid or water from passing downwardly for return to the pump chamber 18.

As the above operation takes place, the water level within the chamber 13 is continually lowered, and ultimately, the float 29 which follows the water level will engage the pivoted yoke 121 and swing the latter downwardly about its pivots 122 suciently to cause the connecting rod 119 and bracket 118 to swing the control arms 75 and 114 downwardly. When this action takes place, the pilot vaive ports '73 are shifted out of registration with the ports 7d, and simultaneously the ports 112 are shifted into registration with the ports 111. As soon as this occurs, compressed air can no longer escape from the chamber 50 through the ports 66 and 67, and the air pressure will rapidly build up in the chamber 58 and cause the air inlet disc valve element 59 to be firmly seated in covering engagement with the ports 46 and 47. When this takes place, the compressed air entering through the oriice 65 and ports A18 and 46 will be unable to unseat the disc valve element 59, due to the fact that the exposed area of this disc valve element at the port 46 is much less than the exposed area on the other side of the valve element 59 at the chamber 58. Consequently, the compressed air will be trapped within the port 46 and cannot ow through the ports 47 to the groove 40 and main inlet passage 37 vof the pump head 14. In other words, no additional compressed air from the pipe 62 will be able to enter the pump chamber 18, once the pilot valve ports 73 and 74 are moved out of registration by the engagement of the oat 29 with the pivoted yoke 121.

Simultaneously with the above, because the pilot valve ports 111 and 112 are in registration or open, the air under pressure can exhaust from the chamber 100 of the d air exhaust valve means, through the ports 105 and 106 and the elbow 107, Figure 6. When this happens, the compressed air within the pump chamber 18 may ow into the passage S9, groove 86 and ports 8S and S1. The compressed air in the axial port S1 will now readily unseat the disc valve element MP1 and the air will pass through the several ports 82 and enter the passage 79, which leads to the exhaust pipe 99 which is open to the atmosphere. ln this situation, the water within the well will feed by gravity through the strainer 20 and into the passage 19 and ports Z2 and 23. This incoming water will readily unseat the foot valve ring 28, whose Iupward movement is limited by the xed washer 123,

and the water level within the chamber 18 will immediately begin to rise and the oat 29 will again be elevated. As soon as the float reaches the level of the bracket 118, its bumper washer 39 will engage this bracket and the arms 75 and 11d will be re-elevated to the approximately horizontal positions shown in Figure 2. This will immediately place the ports 73 and 74 in open registration, Figure 5, and will again shift the ports 112 out of registration with the ports 111. It should new be obvious that when this occurs, compressed air from the delivery pipe 62 will again enter the pump chamber 18 through the passage 37, and simultaneously, the compressed air within the pump chamber 13 will not be able to escape or exhaust through the exhaust pipe 9d. Consequently, the pumping cycle above described will be repeated, and the water within the chamber 1S will be displaced by the compressed air and the water will be discharged upwardly through the pipes 24 and 34.

lt should now be apparent that the above cycle ot operation as controlled by the float 29 and associated elements is continuous, and a substantially continuous flow of liquid will be available at the pipe 12.

It will also be observed that the present pneumatic displacement pump embodies the absolute minimum of moving parts, and the neoprene disc valve elements 59 and 101 actually constitute the only moving parts of the compressed air inlet and exhaust valve means housed within the pump head 14. All springs and like elements, normally subject to wear and corrosion, have been eliminated. lf it should become necessary to replace the neoprene valve elements S9 and 101, it is merely necessary to unserew the removable valve bodies 39, 49, 78 and 92, and access is readily had to the interiors of the bores 36 and 76.

lt will be further observed that the pump head 14 is provided with a pair of removable screw-threaded plugs 124, adjacent the ports 6@ and 163. The purpose of these plugs is merely to facilitate interconnecting a pair of the air displacement pumps in accordance with the present invention, for various heavy duty pumping needs, such as supplying liquid for tire fighting or for other similar purposes. The plugs 12dmay be omitted entirely, if preferred.

The overall construction of the pneumatic displacement pump herein, particularly the construction and operation of the air intake and exhaust valve means described above in detail, is greatly simplified and much more compact and also more ellicient in operation than the corresponding means utilized in prior art pumps of this general category.

It is to be understood that the form of the invention herewith shown and described is to be taken as a preferred example of the same, and that various changes in the shape, size and arrangement of parts may be resorted to, without departing from the spirit of the invention or scope of the subjoined claims.

Having thus described my invention, I claim:

l. A pneumatic displacement pump comprising a pump barrel having liquid inlet foot valve means, a liquid discharge pipe extending into said pump barrel and adapted to convey liquid therefrom, an upper head for said pump barrel having a pair of bores formed therein, compressed air inlet and exhaust pipes connected with said upper head and communicating respectively with said bores, said upper head having main air inlet and exhaust passages communicating with said bores and the interior et the pump barrel, relatively stationary air inlet and exhaust valve bodies removably mounted within said bores of the upper head and having port means in cornmunication with said pipes and said main passages, movable disc valve elements mounted within said bores and shittable in response to changes in air pressure into and out of covering relation with said port means of said valve bodies, pilot valves connected with said upper head and communicating with said bores of. the head adjacent corresponding sides of the disc valve elements, and oat operated means within the pump barrel connected with said pilot valves to operate the latter.

2. A pneumatic displacement pump comprising a pump barrel, a rst head secured to one end of the pump barrel and provided with a pair of bores, compressed air inlet and exhaust valve bodies secured within said bores and having air passage means and dehning chambers within said bores, inlet and exhaust disc valve elements shiftably mounted within said chambers of the bores, pilot valves connected with said head and communicating with said chambers for controlling the pneumatic pressure within said chambers upon corresponding sides of the disc valve elements, lloat means within said pump barrel for operating the pilot valves so that pneumatic pressure is built up in one of said chambers and simultaneously reduced in the other chamber, and foot valve means for the lower end of the pump barrel for admitting liquid under a hydrostatic head into the pump barrel whenever the pneumatic pressure within the pump barrel is reduced.

3. A pneumatic displacement pump comprising a pump barrel, a iirst head secured to one end of the pump barrel and having a pair of bores formed therethrough, compressed air inlet and exhaust valve bodies positioned within said bores and having port means communicating with the interior otv the pump barrel and delining chambers within said bores, air inlet and exhaust disc valve elements movably mounted within said chambers, pilot valves connected with said head and communicating with said chambers and operable for regulating the pneumatic pressure upon corresponding sides of said disc valve elements, one ot' said pilot valves being normally closed when the other pilot valve is open, a float disposed within the pump barrel, linkage means connected with the pilot valves to operate the same and actuated by the rise and fall of thc said float, a second head secured to the pump barrel at its opposite end, and foot valve means associated with the second head for admitting liquid into the pump barrel.

4. A pneumatic displacement pump comprising a pump barrel, a tirst head for the pump barrel having a pair of bores formed therethrough, a pair of valve body por-v tions removably mounted within each bore of said head in axially spaced relation and dening chambers in said bores between adjacent ends of the valve body portions, said valve body portions having air passage means formed therein communicating with the interior of said pump barrel, a disc valve element movably mounted within each of said chambers and shiftable by pneumatic pressure between the adjacent ends of the valve body portions within said bores, a pair of pilot valves connected with said head and communicating with said chambers of the bore for controlling the pneumatic pressure upon one side of each of said disc valve elements, iloat operated means connected with said pilot valves to actuate the same simultaneously, said lloat operated means opening one pilot valve when it closes the other pilot valve, a second head for the pump barrel, and foot valve means associated with said second head for controlling the admission ot liquid into the pump barrel during each cycle of operation of the pump.

5. A pneumatic displacement pump comprising a pump barrel, a head secured to the lower end of the pump barrel and having liquid inlet passage means, a foot valve element disposed within the pump barrel and adapted to cover said passage means and to be unseated by hydrostatic pressure to admit liquid into the pump barrel, said pump barrel having liquid outlet passage Ameans communicating with the interior of the pump barrel, a float disposed within said pump barrel to rise and fall with the level of the liquid therein, a second head secured to the top of the pump barrel and having a pair of bores formed therethrough and passages leading from said hores to the interior of' the pump barrel, a pair of pipes connected with the last-named head and communicating with said bores, a pair of spool-like valve body portions mounted within each bore in axially spaced relation to deue within each bore a chamber between the spool-like valve body portions, a movable disc valve element disposed within each chamber and being shiftable between said pair of valve body portions within the bore, a pair of pilot valves connected with said second head and communicating with said chambers for controlling the pneumatic pressure within the chambers upon one side of the disc valve barrel, upper and lower pump heads connected with said barrel and defining therewith a pump chamber, foot valve means associated with the lower pump head to control the admission of liquid into said chamber, a liquid discharge pipe communicating with said pump chamber and adapted to receive liquid therefrom when said chamber is subjected to air pressure, said upper pump head having a pair of bores formed therein, a pair of relatively stationary air inlet and exhaust valve bodies arranged in spaced relation within each bore and defining a chamber within each bore between said valve bodies, said valve bodies having passage means communicating with said chambers of the bores, a movable disc valve element mounted within each chamber of each bore between said spaced valve bodies and shiftable in response to changes in air pressure into andout of engagement with the opposed ends of said valve bodies for covering and uncovering the passage means of the valve bodies, pilot valve means connected with said upper pump head and cornmunicating with said bores adjacent corresponding sides of the disc valve elements, and float operated means within the pump barrel connected with the pilot valve means to operate the same.

References Cited in the le of this patent UNITED STATES PATENTS 

